Mumble is a "Voice over IP" application, which is useful for gaming for example since it has low latency and nice voice quality. Its permission system is very advanced. The tchncs.de Mumbleserver offers a voice transmission of max. 320kb/s. Your Client however is able to handle up to 124,8kb/s, but for example musicbots can deliver the maximum quality. This Mumbleserver guarantees undisturbed conferences since users, registered by moderators can hide in exclusive channels. Moderators are in the serverdescription, which pops up right after your join.
Feel free to request getting converted to an account or talk in the guest channel tree.
tchncs.de is using an 4096bit LetsEncrypt TLS certificate for e.g. chatting and is using 128 bit OCB-AES128 voice encryption.